/* ===== CSS Variables ===== */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #dbeafe;
  --success: #10b981;
  --warning: #f59e0b;
  --pink: #ec4899;
  --purple: #8b5cf6;
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #1e293b;
  --muted: #64748b;
  --border: #e2e8f0;
  --code-bg: #1e293b;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

/* ===== Reset & Base ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* ===== Container ===== */
.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* ===== Header ===== */
header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
}

.logo:hover {
  text-decoration: none;
}

nav {
  display: flex;
  gap: 1.5rem;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}

nav a:hover,
nav a.active {
  color: var(--primary);
  text-decoration: none;
}

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.mobile-menu-btn span {
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: 0.3s;
}

/* ===== Footer ===== */
footer {
  background: var(--card);
  border-top: 1px solid var(--border);
  padding: 3rem 0 2rem;
  margin-top: 3rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section h4 {
  font-size: 0.9rem;
  margin-bottom: 1rem;
  color: var(--text);
}

.footer-section ul {
  list-style: none;
}

.footer-section li {
  margin-bottom: 0.5rem;
}

.footer-section a {
  color: var(--muted);
  font-size: 0.9rem;
}

.footer-section a:hover {
  color: var(--primary);
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.9rem;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  padding: 1rem 0;
  font-size: 0.9rem;
  color: var(--muted);
}

.breadcrumb a {
  color: var(--muted);
}

.breadcrumb a:hover {
  color: var(--primary);
}

.breadcrumb .separator {
  margin: 0 0.5rem;
}

/* ===== Hero Sections ===== */
.hero {
  background: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  color: white;
  padding: 3rem 0;
  text-align: center;
}

.hero h1 {
  font-size: 1.5rem;
  font-weight: 400;
  opacity: 0.9;
  margin-bottom: 1rem;
}

.hero-display {
  font-size: 3.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.hero-sub {
  font-size: 1.25rem;
  opacity: 0.9;
}

.format-hero {
  background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
  color: white;
  padding: 3rem 2rem;
  margin-bottom: 2rem;
  text-align: center;
  border-radius: var(--radius);
}

.format-hero h1 {
  font-size: 3rem;
  font-weight: 700;
  font-family: 'SF Mono', Monaco, 'Courier New', monospace;
  letter-spacing: 2px;
}

.format-hero .example {
  font-size: 1.5rem;
  opacity: 0.9;
  margin-top: 0.5rem;
}

.format-hero .tags {
  margin-top: 1rem;
}

.tag {
  display: inline-block;
  background: rgba(255, 255, 255, 0.2);
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.85rem;
  margin: 0.25rem;
}

/* ===== Cards ===== */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

/* ===== Format Cards ===== */
.formats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.format-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  position: relative;
  transition: all 0.2s;
}

.format-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow);
}

.format-card.featured {
  border: 2px solid var(--primary);
  background: linear-gradient(to bottom right, #eff6ff, #ffffff);
}

.format-label {
  font-size: 0.8rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.badge {
  background: var(--primary);
  color: white;
  padding: 0.15rem 0.5rem;
  border-radius: 9999px;
  font-size: 0.65rem;
}

.format-value {
  font-size: 1.75rem;
  font-weight: 700;
  font-family: 'SF Mono', Monaco, 'Courier New', monospace;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.format-description {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
}

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-primary:hover {
  background: var(--primary-dark);
  text-decoration: none;
}

.copy-btn {
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.8rem;
  color: var(--muted);
  transition: all 0.2s;
}

.copy-btn:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

.copy-btn.copied {
  background: var(--success);
  color: white;
  border-color: var(--success);
}

/* ===== Tables ===== */
.table-wrapper {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: var(--bg);
  font-size: 0.8rem;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 600;
}

tr:hover {
  background: #f8fafc;
}

.format-code {
  font-family: 'SF Mono', Monaco, 'Courier New', monospace;
  font-weight: 600;
  color: var(--primary);
}

/* ===== Code Blocks ===== */
.code-section {
  margin-bottom: 1.5rem;
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #334155;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

.code-lang {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: white;
  font-weight: 600;
}

.code-block {
  background: var(--code-bg);
  color: #e2e8f0;
  padding: 1.25rem;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  overflow-x: auto;
  font-family: 'SF Mono', Monaco, 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.7;
}

.code-block code {
  white-space: pre-wrap;
  word-break: break-word;
}

/* ===== Quick Info ===== */
.quick-info {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.info-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1rem;
  text-align: center;
}

.info-item .label {
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
}

.info-item .value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}

/* ===== Sections ===== */
section {
  margin-bottom: 2.5rem;
}

section h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

section h3 {
  font-size: 1.1rem;
  margin: 1.5rem 0 0.75rem;
}

/* ===== Meaning Grid ===== */
.meaning-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.meaning-item {
  background: var(--primary-light);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
}

.meaning-item .symbol {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
  font-family: 'SF Mono', Monaco, monospace;
}

.meaning-item .label {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.5rem;
}

.meaning-item .range {
  font-weight: 600;
  margin-top: 0.25rem;
}

/* ===== Warning Box ===== */
.warning-box {
  background: #fef3c7;
  border-left: 4px solid var(--warning);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
}

.warning-box strong {
  color: #92400e;
}

/* ===== Tip Box ===== */
.tip-box {
  background: #ecfdf5;
  border-left: 4px solid var(--success);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
}

.tip-box strong {
  color: #047857;
}

/* ===== Related Grid ===== */
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}

.related-link,
.related-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1rem;
  text-decoration: none;
  color: var(--text);
  transition: all 0.2s;
}

.related-link:hover,
.related-item:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  text-decoration: none;
}

.related-link .title,
.related-item .format {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.related-item .format {
  font-family: 'SF Mono', Monaco, monospace;
  color: var(--primary);
}

.related-link .desc,
.related-item .desc {
  font-size: 0.85rem;
  color: var(--muted);
}

/* ===== FAQ ===== */
.faq-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  margin-bottom: 0.75rem;
}

.faq-question {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.faq-answer {
  color: var(--muted);
  font-size: 0.95rem;
}

/* ===== Converter ===== */
.converter-tool {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 2rem;
}

.converter-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1.5rem;
  align-items: end;
}

.converter-panel {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.converter-panel label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.converter-panel select,
.converter-panel input {
  width: 100%;
  padding: 0.875rem 1rem;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  background: white;
  margin-bottom: 1rem;
}

.converter-panel select:focus,
.converter-panel input:focus {
  outline: none;
  border-color: var(--primary);
}

.result-display {
  background: white;
  border: 2px solid var(--primary);
  border-radius: var(--radius-sm);
  padding: 1rem;
  font-family: 'SF Mono', Monaco, monospace;
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--primary);
  text-align: center;
  min-height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.swap-btn {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  transition: transform 0.3s;
}

.swap-btn:hover {
  transform: rotate(180deg);
}

/* ===== Birthday Tool ===== */
.birthday-tool {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 2rem;
}

.birthday-input-row {
  display: flex;
  gap: 1rem;
  justify-content: center;
  align-items: end;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.birthday-field {
  text-align: center;
}

.birthday-field label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.birthday-field select,
.birthday-field input {
  padding: 0.875rem 1rem;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1.1rem;
  text-align: center;
  min-width: 100px;
}

.birthday-results {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.result-item {
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1rem;
  text-align: center;
}

.result-item .format-name {
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}

.result-item .format-value {
  font-size: 1.25rem;
  font-weight: 600;
  font-family: 'SF Mono', Monaco, monospace;
  color: var(--pink);
  margin-bottom: 0.5rem;
  justify-content: center;
}

/* ===== Country ===== */
.country-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  margin: 0.25rem;
}

.country-tag .flag {
  font-size: 1.25rem;
}

.countries-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* ===== Languages Grid ===== */
.lang-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
}

.lang-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1rem;
  text-decoration: none;
  color: var(--text);
  text-align: center;
  transition: all 0.2s;
}

.lang-item:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  text-decoration: none;
}

.lang-item .icon {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.lang-item .name {
  font-weight: 600;
}

/* ===== Format Table ===== */
.format-table {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.format-table code {
  background: var(--bg);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-family: 'SF Mono', Monaco, monospace;
  font-size: 0.9rem;
}

/* ===== Conversions Grid ===== */
.conversions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.conversion-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-decoration: none;
  color: var(--text);
  transition: all 0.2s;
}

.conversion-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  text-decoration: none;
}

.conversion-card .from-to {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.conversion-card .format {
  font-family: 'SF Mono', Monaco, monospace;
  font-weight: 600;
  font-size: 0.9rem;
}

.conversion-card .arrow {
  color: var(--primary);
}

.conversion-card .desc {
  font-size: 0.85rem;
  color: var(--muted);
}

/* ===== Steps ===== */
.steps {
  counter-reset: step;
}

.step {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.step:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.step-number {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--purple));
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  flex-shrink: 0;
}

.step-content h4 {
  margin-bottom: 0.5rem;
}

.step-content p {
  color: var(--muted);
  margin-bottom: 0;
}

.step-content .example {
  background: var(--bg);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-family: 'SF Mono', Monaco, monospace;
  display: inline-block;
  margin-top: 0.5rem;
}

/* ===== Home Page ===== */
.home-hero {
  text-align: center;
  padding: 4rem 0;
}

.home-hero h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.home-hero p {
  font-size: 1.2rem;
  color: var(--muted);
  max-width: 600px;
  margin: 0 auto 2rem;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .converter-grid {
    grid-template-columns: 1fr;
  }

  .swap-btn {
    transform: rotate(90deg);
    margin: 0 auto;
  }

  .swap-btn:hover {
    transform: rotate(270deg);
  }

  .hero-display {
    font-size: 2.5rem;
  }

  .format-hero h1 {
    font-size: 2rem;
  }

  .format-value {
    font-size: 1.25rem;
  }
}

@media (max-width: 640px) {
  nav {
    display: none;
  }

  .mobile-menu-btn {
    display: flex;
  }

  nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--card);
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
  }

  nav.open a {
    padding: 0.75rem 0;
  }

  .meaning-grid {
    grid-template-columns: 1fr;
  }

  .home-hero h1 {
    font-size: 2rem;
  }
}